The Utility of Mitochondrial Detection Methods Applied as an Additional Tool for the Differentiation of Renal Cell Tumors.

The precise differentiation of renal cell tumors (RCTs) is sometimes hard to achieve using standard imaging and histopathological methods, especially for those with eosinophilic features. It has been suggested that the vast overabundance of mitochondria, as a well-known hallmark of eosinophilic cytoplasm, and could be a characteristic of distinct tumor types with opposing clinical outcomes. Thus, we intended to explore the associations between mitochondrial distribution patterns in different RCTs, including 43 cell renal cell carcinomas (ccRCCs), 15 papillary renal cell carcinomas (pRCCs), 20 chromophobe renal cell carcinomas (chRCCs), and 18 renal oncocytomas (ROs). Tumor samples were stained with two anti-mitochondrial antibodies (mitochondrial antibody Ab-2, clone MTC02; prohibitin, II-14-10, MA5-12858), applying immunohistochemistry and immunofluorescence to define mitochondrial distribution patterns (coarse scanty, moderate granular, and diffuse granular). Our results revealed significantly different expression patterns among the investigated RCTs (p < 0.001). The majority of ccRCCs exhibited coarse scanty mitochondrial staining, while all chRCCs had moderate granular expression. Nevertheless, all ROs, all pRCCs, and two cases of ccRCC presenting with higher nuclear grade and eosinophilic cytoplasm had diffuse granular mitochondrial expression. Moreover, with increased distribution of mitochondria, the intensity of staining was higher (p < 0.001). Here we present a strategy that utilizes fast and easy mitochondrial detection to differentiate RO from chRCC, as well as other eosinophilic variants of RCC with high accuracy.

Effects of Automation on Sustainability of Immunohistochemistry Laboratory.

The COVID-19 pandemic that hit the world recently caused numerous changes affecting the health system in every department. Reduced staff numbers, mostly due to illness, led to an increase in automation at every stage of laboratory work. The immunohistochemistry (IHC) laboratory conducts a high volume of slide staining every day. Therefore, we analyzed time and total costs required to obtain IHC slides in both the manual and automated way, comparing their efficiency by processing the same sample volume (48 microscope slides-the maximum capacity that an automated immunostainer-DAKO, Autostainer Link 48, Part No AS48030-can process over a single cycle). The total IHC procedure time to run 48 slides manually by one technician was 460 min, while the automated process finished a cycle within 390 min (15.22% less time). The final cost of a single manual IHC slide was 12.26 EUR and 7.69 EUR for slides labeled in the automated immunostainer, which reduced final costs by 37.27%. Thus, automation of the IHC procedure reduces the time and costs of the IHC process, contributing significantly to the sustainability of the healthcare system during the COVID-19 pandemic, overcoming insufficient human resources.

Expression of kisspeptin and KISS1 receptor in pituitary neuroendocrine tumours - an immunohistochemical study.

INTRODUCTION: Pituitary neuroendocrine tumours (PitNETs), traditionally designated as pituitary adenomas, show elatively frequent invasive growth with exceptional metastatic potential, the causes of which are not entirely elucidated. Kisspeptins, which perform their activity through KISS1 receptor (KISS1R), are recognised as metastatic suppressors in many malignant tumours. This study aimed to investigate the immunohistochemical expression of kisspeptin and KISS1R in different types of PitNETs and to compare it with the expression in the normal anterior pituitary, using tissue microarray. MATERIAL AND METHODS: The experimental group consisted of 101 patients with PitNETs, with 45 (37.3%) being of gonadotroph, 40 (33.9%) somatotroph, 4 (3.4%) corticotroph, 4 (3.4%) thyrotroph, 3 (2.5%) lactotroph, and 6 (5.1%) null-cell type. The control group consisted of anterior pituitary tissue accidentally removed during the surgery for PitNETs in 17 patients. RESULTS: Kisspeptin expression was observed in both experimental and control groups, without statistically significant differences in the staining intensity. Negative kisspeptin staining was detected in 10 (9.9%), weak in 79 (78.2%), and moderate in 12 tumours (11.9%); none of the tumours had strong staining intensity. The weak staining intensity was predominant in all PitNET types except thyrotroph tumours. Significant statistical difference in terms of kisspeptin expression between types of PitNET and the control group was not observed. Immunohistochemical expression of KISS1R was not observed in the control group or in the experimental group. CONCLUSIONS: We conclude that immunohistochemistry, as a method, cannot confirm the involvement of kisspeptin in tumourigenesis and aggressiveness of PitNETs, but potentially supports its antimetastatic role. The absence of KISS1R immunohistochemical expression in all anterior pituitaries and PitNETs in our cohort needs verification through the use of different procedures designed for the detection of the presence and localisation of proteins in the cell.

PRMT1 expression in renal cell tumors- application in differential diagnosis and prognostic relevance.

BACKGROUND: Protein arginine methyltransferase-1 (PRMT1) is associated with the progression of various tumor types and the process of epithelial to mesenchymal transition (EMT). However, the expression of PRMT1 in renal cell tumors (RCT) is unknown. METHODS: We evaluated PRMT1 immunohistochemical (IHC) expression on tissue microarray (TMA) of 208 specimens of RCT, including clear cell renal cell carcinomas (ccRCC), papillary RCC type I and II (pRCC I and II), chromophobe RCC (chRCC), renal oncocytomas (RO), collecting duct carcinomas - Bellini (CDC) and multilocular cystic renal cell neoplasms of low malignant potential (MLCRN-LMP). Moreover, a subset of ccRCC, pRCC, chRCC, RO were also studied using conventional sections. PRMT1 expression in tumor tissue was compared to the IHC expression of EMT-related transcription factors (ZEB1, RUNX1, and TWIST1) and cell surface markers (ß-catenin, N- and E-cadherin). Additionally, qRT-PCR expression of PRMT1 in ccRCC, pRCC, and chRCC was evaluated and the results were compared to the mRNA PRMT1 transcript profiling data in The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) cohort. RESULTS: PRMT1 immunoreactivity was observed in the majority of ccRCC, RO, all MLCRN-LMP, but in a minority of chRCC (p = 0.044), and it was associated with low grade and low stage ccRCC (p = 0.014; p = 0.044, respectively). ZEB1 immunoreactivity was noted in all RO, in minority of chRCC and neither of MLCRN-LMP (p < 0.001). The majority of PRMT1-negative ccRCC was negative to ZEB1 and showed cytoplasmic expression of TWIST1 (p = 0.028; p < 0.001, respectively). PRMT1 positive ccRCC mostly expressed RUNX1 (p = 0.019). PRMT1 and ZEB1 expression were associated with better cancer-specific survival in patients with ccRCC (p = 0.029; p = 0.009, respectively). In multivariate analysis, ZEB1 expression was an independent prognostic factor for cancer-specific survival (hazard ratio [HR], 0.367; p = 0.026). Significant IHC heterogeneity was observed in PRMT1, ZEB1 and TWIST1 expression (p < 0.001). Homogenous loss of PRMT1 was associated with high grade and high stage ccRCC, while the homogenous loss of PRMT1 and ZEB1 was more frequent in patients who died of ccRCC (p = 0.017; p = 0.040; p = 0.044; p = 0.009, respectively). Relative mRNA-PRMT1 expression in both cohorts was down-regulated in tumor tissue compared to non-tumor parenchyma (p = 0.009). Unlike in our samples, mRNA-PRMT1 expression in the TCGA cohort was not correlated to ccRCC tumor stage or grade. PRMT1, ZEB1, and TWIST1 expression were not associated with EMT related aberrant ß-catenin expression, a gain of N-cadherin or loss of E-cadherin expression. Only RUNX1 was associated with a gain of N-cadherin (p = 0.003). CONCLUSIONS: IHC expression of PRMT1 may be characteristic for low grade and low stage ccRCC, while the homogenous loss of PRMT1 may be significant for high grade and high stage ccRCC. Both, PRMT1 and/or ZEB1 expression, could be associated with better survival of the patients with ccRCC.

Expression of p300 and p300/CBP associated factor (PCAF) in actinic keratosis and squamous cell carcinoma of the skin.

p300 and p300/CBP-associated factor (PCAF) are histone modifiers and transcriptional co-factors involved in a number of cell processes. We investigated their expression patterns in 79 actinic keratoses (AK), 45 cases of Bowen's disease (BD), and 168 invasive squamous cell carcinomas of the skin (SCC). Using tissue microarray and immunohistochemistry, we evaluated p300 and PCAF expression in relation to the type of the lesion and SCC prognostic parameters (grade, diameter, thickness and level of invasion). High nuclear expression of p300 (>60% of positive cells) (p=0.001) and absent cytoplasmic expression (p=0.026) were more frequent in SCC compared to AK and BD, respectively. Cytoplasmic expression of p300 was associated with the SCC invasion of subcutaneous fat and deeper tissues (p=0.049). Diffuse distribution of cells with p300 nuclear expression was more commonly seen in BD and SCC compared to AK (p<0.001), in moderately- and poorly-differentiated SCC compared to well-differentiated SCC (p<0.001), in tumors thicker than 6mm (p<0.001), and in deeply invading tumors (p=0.001). More frequent loss of PCAF nuclear expression was observed in SCC than in AK and BD (p<0.001). Diffuse distribution of cells with PCAF cytoplasmic expression was more common in BD and SCC compared to AK (p<0.001), and in poorly-differentiated SCC compared to well- and moderately-differentiated SCC (p<0.001). Our results suggest that increase in nuclear expression of p300, as well as the presence of cytoplasmic but loss of nuclear expression of PCAF, could play an important role in the development and progression of cutaneous SCC.

Immunolocalization of the TASK2 Potassium Channel in Frog Kidney.

TASK2 (K2P5. 1, KCNK5) is a two-pore domain K⁺ channel belonging to the TALK subgroup of the K2P family of proteins. TASK2 expression has been reported in a variety of cells and tissues ranging from kidney to immune cells and including specific neurons, its proposed functions spanning from involvement in the regulation of cell volume to control of excitability. The purpose of this study was to determine the tubule location ofthe TASK2 K⁺ channel protein in frog kidney applying polyclonal antibody against the carboxyl terminus of human TASK2 (KCNK5) protein. Immunohistochemical analysis revealed that TASK2 is expressed on distal tubules and proximal epithelial cells. TASK2 is strongly expressed predominantly on the luminal part ofthe proximal epithelial cells and slightly cytoplasmatic staining is expressed. Distal tubules showed diffuse cytoplasmatic staining as well as slight staining on the apical parts ofthe cells. These findings suggest that the TASK2 K⁺ channel has cell-specific roles in renal potassium ion transport.

Variable Expression of Neural Cell Adhesion Molecule Isoforms in Renal Tissue: Possible Role in Incipient Renal Fibrosis.

Rare neural cell adhesion molecule (NCAM) positive cells have been previously described within the normal human adult kidney interstitium, speculating that they could increase in the interstitium with incipient interstitial renal fibrosis (IRF). In the present study, among 93 biopsy samples of various kidney diseases, NCAM+ interstitial cells were detected in 62.4% cases. An increased number of NCAM+ cells was significantly observed only in incipient IRF compared to normal renal tissues and advanced IRF stages (p<0.001), independently of underlying diseases (p = 0.657). All three major NCAM isoforms' RT-PCR bands were visible either in normal or in kidneys with incipient IRF, albeit their mRNA expression levels measured by qRT-PCR were different. Applying qRT-PCR on pure NCAM+ cells population, obtained by laser capture microdissection, significant mRNA over-expression of NCAM140kD isoform was found in NCAM+ cells within incipient IRF (p = 0.004), while NCAM120kD and NCAM180kD isoforms were not changed significantly (p = 0.750; p = 0.704; respectively). Simultaneously, qRT-PCR also showed significant αSMA (p = 0.014) and SLUG (p = 0.004) mRNAs up-regulation within the NCAM+ cells of incipient IRF, as well as highly decreased matrix metalloproteinases (MMP) -2 and -9 mRNAs (p = 0.028; p = 0.036; respectively). However, using double immunofluorescence MMP-9 could still be detectable on the protein level in rare NCAM+ cells within the incipient IRF. Further characterization of NCAM+ cells by double immunofluorescent labeling revealed their association with molecules involved in fibrosis. Fibroblast growth factor receptor 1 (FGFR1) and α5ß1 integrin were extensively expressed on NCAM+ cells within the incipient IRF areas, whereas human epididymis protein-4 (HE4) was found to be present in few NCAM+ cells of both normal and interstitium with incipient fibrosis. Heterogeneity of NCAM+ interstitial cells in normal and incipient IRF, concerning molecules related to fibrosis and variable expression of NCAM isoforms, could suggest diverse role of NCAM+ cells in homeostasis and in regulation of renal fibrosis in diseased kidneys.

Glomerular nestin expression: possible predictor of outcome of focal segmental glomerulosclerosis in children.

BACKGROUND: A high prevalence of chronic kidney disease among children with focal segmental glomerulosclerosis (FSGS) leads to a permanent quest for good predictors of kidney dysfunction. Thus, we carried out a retrospective cohort study in order to examine known clinical and morphological predictors of adverse outcome, as well as to investigate glomerular nestin expression as a potential new early predictor of kidney dysfunction in children with FSGS. Relationships between nestin expression and clinical and morphological findings were also investigated. METHODS: Among 649 renal biopsy samples, obtained from two children's hospitals, FSGS was diagnosed in 60 children. Thirty-eight patients, who met the criteria for this study, were followed up for 9.0 ± 5.2 years. Using Kaplan-Meier and Cox's regression analysis, potential clinical and morphological predictors were applied in two models of prediction: after disease onset and after the biopsy. RESULTS: The present study revealed the following significant predictors of kidney dysfunction: patients' ages at disease onset, as well as age at biopsy, resistance to corticosteroid treatment, serum creatinine level, urine protein/creatinine ratio, vascular involvement, tubular atrophy, interstitial fibrosis, and decreased glomerular nestin expression. CONCLUSIONS: The most important finding of our study is that nestin can be used as a potential new early morphological predictor of kidney dysfunction in childhood onset of FSGS, since nestin has been obviously decreased in both sclerotic and normal glomeruli seen by light microscopy.

NCAM and FGFR1 coexpression and colocalization in renal tumors.

Neural cell adhesion molecule (NCAM) and fibroblast growth factor receptor (FGFR) have a role in epithelial-mesenchymal transformation during tumor genesis. Interplay between both molecules activates FGFR signaling and it could be responsible for tumor development. Renal epithelial tumors were analyzed for FGFR1 and NCAM coexpression by immunohistochemistry and for colocalization of these molecules on the particular tumor cells by triple immunofluorescence. Detection of NCAM isoforms in renal tumors was evaluated by RT-PCR. Applying immunohistochemistry we revealed that the majority of analyzed renal neoplasms, including renal cell carcinoma (RCC) and oncocytoma coexpressed NCAM and FGFR1. Triple immunofluorescent technique confirmed that both markers are commonly colocalized on the same tumor cells. Interestingly, it seemed that different position of NCAM and FGFR1 expression on renal tumor cells is related to renal tumor type or grade: exclusively membranous FGFR1/NCAM expression occurred in low grade clear cell RCC (cRCC); cytoplasmatic and membranous expression was present in high grade cRCC and other RCC types; oncocytoma showed only cytoplasmatic staining of both markers. NCAM-140 and NCAM-120 were detected in almost all analyzed renal neoplasms. Expression of both molecules on different cell compartments in various kidney tumors indicated that NCAM/FGFR1 interaction could play distinct roles in renal tumor genesis.

Losartan improved antioxidant defense, renal function and structure of postischemic hypertensive kidney.

Ischemic acute renal failure (ARF) is a highly complex disorder involving renal vasoconstriction, filtration failure, tubular obstruction, tubular backleak and generation of reactive oxygen species. Due to this complexity, the aim of our study was to explore effects of Angiotensin II type 1 receptor (AT1R) blockade on kidney structure and function, as well as oxidative stress in spontaneously hypertensive rats (SHR) after renal ischemia reperfusion injury. Experiments were performed on anaesthetized adult male SHR in the model of ARF with 40 minutes clamping the left renal artery. The right kidney was removed and 40 minutes renal ischemia was performed. Experimental groups received AT1R antagonist (Losartan) or vehicle (saline) in the femoral vein 5 minutes before, during and 175 minutes after the period of ischemia. Biochemical parameters were measured and kidney specimens were collected 24 h after reperfusion. ARF significantly decreased creatinine and urea clearance, increased LDL and lipid peroxidation in plasma. Treatment with losartan induced a significant increase of creatinine and urea clearance, as well as HDL. Lipid peroxidation in plasma was decreased and catalase enzyme activity in erythrocytes was increased after losartan treatment. Losartan reduced cortico-medullary necrosis and tubular dilatation in the kidney. High expression of pro-apoptotic Bax protein in the injured kidney was downregulated after losartan treatment. Our results reveal that angiotensin II (via AT1R) mediates the most postischemic injuries in hypertensive kidney through oxidative stress enhancement. Therefore, blockade of AT1R may have beneficial effects in hypertensive patients who have developed ARF.

Expression of neural cell adhesion molecule in renal cell carcinoma.

Neural cell adhesion molecule (NCAM) is important for cell migration and it could be expressed in some renal cell carcinoma (RCC). In recent decades, the incidence of RCC has been steadily rising by 2-4% each year. In this study NCAM expression and correlation with nuclear grade in different RCC were analyzed. We analyzed NCAM expression on 7 different RCC cell lines and 32 different RCC by immunohistochemistry, immunofluorescence, Western blot and FACS analysis. NCAM expression is detected in 6 cell lines and 16 RCC cases. NCAM-140 kDa isoform is expressed in different RCC and RCC cell lines. NCAM expression in non-invasive clear cell RCC is lower than in clear cell RCC with high nuclear grade. Expression of NCAM is not exclusive for specific RCC type, so NCAM can not be used as a specific diagnostic marker for RCC. NCAM expression is in correlation with nuclear grade in clear cell RCC, suggesting that NCAM expression is involved in aggressive behavior and metastatic potential in RCC.

The effects of potassium channel opener P1075 on the human saphenous vein and human internal mammary artery.

Because adrenergic contractions can contribute to the development of life-threatening spasm of coronary artery bypass graft, this study was performed to investigate the effect of adenosine 3-phosphate (ATP)-sensitive K channel (KATP) opener P1075 on contractions of isolated human saphenous vein (HSV) and human internal mammary artery (HIMA). Phasic contractions were evoked by electric field stimulation (20 Hz) and noradrenaline. The sustained contractions were evoked by phenylephrine. The presence of pore-forming Kir6.1 and Kir6.2 subunits of the KATP channels in the HIMA and only Kir6.2 in the HSV was confirmed immunomorphologically. P1075 inhibited in the HSV only, the electrical field stimulation contractions more strongly than noradrenaline contractions. In addition, the phenylephrine contractions of HSV were more sensitive to P1075 in comparison to those of HIMA. Glibenclamide, a KATP channel blocker antagonized the vasodilatation produced by P1075 in both grafts differently, because its effect was more prominent on the P1075-induced inhibition of contractions of HSV than of HIMA. We conclude that P1075 has a vasorelaxant effect and inhibited adrenergic contractions of the tested grafts. This effect is graft and vasoconstrictor selective and seems to be mediated by Kir6.1- and/or Kir6.2-containing KATP channels. Thus, P1075 can be considered as a potential drug in the prevention of graft spasm.

Effect of potassium channel opener pinacidil on the contractions elicited electrically or by noradrenaline in the human radial artery.

In order to discover an agent that can prevent spasm of the human radial artery, the aim of our study was to evaluate the effect of the K(+) channel opener, pinacidil, on contractions in the radial artery. Contractions of the radial artery were evoked by exogenously applied noradrenaline or by electrical field stimulation (EFS, 20Hz, neurogenic). Pinacidil induced concentration-dependent inhibition of both EFS- and noradrenaline-evoked contractions of the radial artery. Glibenclamide, a selective blocker of ATP-sensitive K(+) channels (Kir6.x containing subunit) antagonized in the same manner the pinacidil-induced inhibition of neurogenic contractions and contractions evoked by exogenous noradrenaline. The inhibition of pinacidil relaxation by tetraethylammonium (TEA), a blocker of Ca-sensitive K(+) (K(Ca)) channels, was more pronounced in EFS-contracted preparations. A blocker of voltage-sensitive K(+) (K(V)) channels, 4-aminopyridine (4-AP), inhibited pinacidil relaxation only in EFS-contracted preparations. In order to test the presence of different K(+) channels, immunohistochemistry of K(+) channels expression in the radial artery was performed. The vascular wall of the human radial artery showed variable positivity with the following applied antibodies: Kv1.2, Kv1.3, Kir6.1, and K(Ca)1.1. The antibodies against Kv1.6, Kv2.1, and Kir6.2 channel subunits were completely negative. These results suggest that the inhibitory effect of pinacidil on contractions of the human radial artery might be postsynaptic and associated with opening of smooth muscle Kir6.1-containing K(ATP) channels. TEA- and 4-AP-sensitive K(+) channels may also contribute to pinacidil effect in the human radial artery.

[Pax-2 antigen expression in kidney tumours].

UNLABELLED: Pax-2 transcriptional factor is expressed during kidney development and could re-express in renal tumors. The aim of this study was to examine Pax-2 expression in different types of renal cell carcinoma (RCC) in order to see whether it is good immunohistochemical marker. METHOD: We analyzed 48 different renal tumours stained with Pax-2 antibody. Pax-2 positive reaction was noticed in nucleus or cytoplasm. Expression of this antigen in tumours tissue was correlated with tumour stage and nuc-lear grade. Pax-2 expression between different histological RCC types was analyzed by chi2 test and Fishers test for two in-depended samples. RESULTS: Pax-2 is expressed by a high percentage of re-nal tumors regardless of histologic type. Significant diffe-rence of Pax-2 expression between oncocytomas and chromofobe RCC was found. CONCLUSION: Nuclear expression of Pax-2 is useful diagnostic kidney tumour marker. Pax-2 showed stronger expression in lower malignancy kidney tumours and in oncocytomas, than in high grade RCC like in those with sarcomatoid differentiation